An optical module component referred to as an optical receptacle has been used since the past in optical communication using optical fibers. The optical receptacle is configured such that an end portion of an optical fiber held within a cylindrical ferrule is inserted into the optical receptacle together with the ferrule and fixed thereto. In addition, a photoelectric conversion device having a photoelectric conversion element is attached to the optical receptacle. The optical receptacle onto which the photoelectric conversion device and the optical fiber are assembled in this way optically couples the photoelectric conversion element and the end portion of the optical fiber.
Here, FIG. 5 shows an example of this type of optical receptacle 1 (refer to, for example, FIG. 4 of Patent Literature 1). The optical receptacle 1 is integrally formed by injection molding of a light-transmitting resin material, such as polyetherimide (PEI), polycarbonate (PC), polyethersulfone (PES), cyclo olefin polymer (COP), or poly (methyl methacrylate) (PMMA).
As shown in FIG. 5, the optical receptacle 1 has a lens 2 in a substantially center position in a length direction. The lens 2 is formed into a plano-convex lens in which a first face 2a on the upstream side of light in an optical axis OA direction of the lens 2 (upper side in FIG. 5) is a planar face, and a second face 2b on the downstream side of light (lower side in FIG. 5) is a convex face.
In addition, as shown in FIG. 5, the optical receptacle 1 has a photoelectric conversion device attaching section 3 that extends from an outer position in a radial direction of the lens 2 towards the downstream side (lower side in FIG. 5) in the optical axis OA direction. The photoelectric conversion device attaching section 3 is formed into a cylindrical shape of which an inner circumferential surface is a circular cylindrical surface that is concentric with the optical axis OA. However, as shown in FIG. 5, a through-hole 4 is drilled in the photoelectric conversion device attaching section 3 to allow gas to escape outside, the gas being generated from an adhesive (such as thermoset resin) when a photoelectric conversion device is fixed to the photoelectric conversion device attaching section 3 using the adhesive.
Furthermore, as shown in FIG. 5, the optical receptacle 1 has an optical fiber attaching section 5 that extends from the outer position in the radial direction of the lens 2 towards a direction in the optical axis OA direction opposite to the photoelectric conversion device attaching section 3. The optical fiber attaching section 5 is formed into a cylindrical shape of which an inner circumferential surface is a substantially circular cylindrical shape that is concentric with the optical axis OA.
Next, FIG. 6 shows an optical module 7 for reception as an example of an optical module including the optical receptacle 1, such as that described above.
In other words, as shown in FIG. 6, in the optical module 7, a CAN-package-type photoelectric conversion device 8 including an optical reception function is attached to the photoelectric conversion device attaching section 3 of the optical receptacle 1. More specifically, as shown in FIG. 6, the photoelectric conversion device 8 is configured by: a circular disk-shaped stem 9; a light-receiving element 10, such as a photodetector (PD), mounted on the stem 9; a cap 11 having a window portion in the peak portion and disposed such as to cover the light-receiving element 10; and a lead 12 through which electrical signals flow based on a light-reception result (photoelectric conversion) of the light-receiving element 10.
In addition, as shown in FIG. 6, in the optical module 7, an optical fiber 15 is detachably attached, together with a ferrule 17 that holds the optical fiber 15, to the optical fiber attaching section 5.
In the optical module 7 for reception such as that described above, light including transmission information that has been transmitted from a transmission-side device (such as a semiconductor laser LD) is transmitted over the optical fiber 15 and emitted from an end portion (end face) 15a of the optical fiber 15 towards the lens 2. The light emitted towards the lens 2 is then converged by the lens 2 and emitted towards the photoelectric conversion device 8. Thereafter, the light is received by the light-receiving element 10 of the photoelectric conversion device 8. In this way, the end portion 15a of the optical fiber 15 and the light-receiving element 10 are optically coupled.
In the optical module 7, the optical fiber 15 is used so as to be frequently attached and detached to and from the optical fiber attaching section 5, together with the ferrule 17.